I'm afraid I can't give you specifics on piston speed, but that wont stop
me from generalising!!! :-)
I would hypothesise that the frictional losses would increase at a
non-linear
rate as sliding speed increases. Probably more significant is that the
resultant
heat and wear would also increase in a non-linear fashion.
I'd also guess that for say the 1100 A series engine, these effects probably
wouldn't become significant until well past 7000 rpm. This is based on the
redline of equivilent capacity short stroke m/cycle engines.
Mike
----------------------------------------------------------------------------
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Mike Gigante mikeg@vicnet.net.au
Watsons Creek Vineyard http://www.vicnet.net.au/~mikeg
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-----Original Message-----
From: Richard L. Bergstrom <ric_bergstrom@juno.com>
To: mikeg@vicnet.net.au <mikeg@vicnet.net.au>
Date: Monday, January 05, 1998 9:29 AM
Subject: Re: MGA superiority, long strokes, RBB stuff, Fergussons,
Venoliaslugs
>I've been lurking on your thread. Had a thought. When does piston speed
>enter into this? I don't know how to calculate it but I think there is
>an upper limit. I think you'd see the upper limit for "modern"
>technology in a high RPM sportbike or an Acura with the hot motor in it.
>Amazing what we are doing with 30+ year old technology!
>
>
>Ric Bergstrom
>
>On Sun, 4 Jan 1998 18:43:14 +1100 "Mike Gigante" <mikeg@vicnet.net.au>
>writes:
>>Well if long stroke is the reason, then how come an 1100 race spridget
>>can
>>pull 8200 rpm in top gear? This is fact.
>>
>>While it is true that long stroke makes things more difficult, the
>>reason
>>may not
>>be what you think.
>>
>>I'll say again that the key to high rpm is the engines ability to suck
>>fuel/air mixture
>>into the combustion chamber. It so happens that with long stroke, you
>>are
>>forced
>>to use smaller valves than you would otherwise choose to (long stroke
>>means
>>smaller
>>bore for the same capacity; smaller bore means less cross sectional
>>area for
>>the valves)
>>
>>Even so, a long stroker like the 1098cc engine can still be made to
>>pull
>>high relatively
>>high RPM by a combination of cam, porting and big (as possible)
>>valves. In
>>lower gears
>>it would happily pull 9 or 10,000 if allowed to (just before the crank
>>breaks :-)
>>
>>Mike
>>
>>
>>
>>
>
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